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Post by brammy on Aug 19, 2020 17:33:33 GMT -8
I have an Athearn DCC-ready SD70ACE. I put in an NCE 8-bin decoder last year. I forget which one. Last night I had a bad derailment backing over a turnout and created a short. After that, both locos were unresponsive. One of them, I was able to load in Decoder Pro, clear the "stuck in consist" CVs and it was fine.
The second one Decoder Pro wasn't reading. When I used the throttle on my PowerCab it refused to read CVs or decoder type when I brought up programming. So, I figured I cooked the decoder even though I didn't smell anything. So, I replaced the decoder with a spare I had.
Same exact problem still persists. Now, there is a slim chance that spare decoder had a problem I have since forgotten about -- well, given things in life these days it wouldn't surprise me if I forgot. I checked the wiring on the trucks and no cables were loose.
Any troubleshooting steps? I don't have any dummy plugs to test on DC, although my friend may have some extra ones and will bring one this weekend. Where would I put a multimeter to see if trucks are at least picking up power?
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Post by nsc39d8 on Aug 19, 2020 19:19:36 GMT -8
Brammy,
To see if the trucks are picking up power you should put one lead of the multi meter on each side of the DC board where the truck wires feed into the board. From there you can check to see if there is resistance in the orange and gray wires for the motor. If you have a DC power pack you can apply power directly to the motor to see if it is working. If all internal components are working then I would suspect the decoder.
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Post by edwardsutorik on Aug 19, 2020 19:34:51 GMT -8
The short that you describe doesn't run excess power through the decoder, or motor. It runs it through the command station/booster/whatever.
I recommend putting a "fresh" loco on the track and see if you can run ANYTHING.
If not, deal with the command station....
If your test loco runs just fine, you likely "confused" your decoders. As opposed to destroying them. I think I would hit the decoder clear button (CV8?) and reprogram.
As an aside, I write down any changes that I make to CV's, so I can easily reprogram from my crib sheet.
Ed
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Post by brammy on Aug 20, 2020 4:52:41 GMT -8
My setup is this:
- NCE PowerCab
- NCE SmartBooster 5
My programming track is:
- Same PowerCab
- NCE PCP
- NCE USB connection for Decoder Pro
The command station is fine. I can run other locomotives. Also, while the PowerCab is the same command station for both the layout and the programming track, I can program other locomotives just fine.
This unit, though, both the PowerCab and DecoderPro refuse to acknowledge the existence of. The PowerCab refuses to pull up decoder manufacturer or read the CVs. For giggles, I did the NCE-based reset and no joy. Likewise, DecoderPro refuses to either identify the locomotive (it already has a roster entry), or detect it when I create a new entry.
I did swap it out with another 8-pin decoder. Now, it is possible, although rare, both decoders have issues. What I will try doing this weekend when I take it apart again is put the decoder in another locomotive and test it.
The other unit after the aforementioned short was stuck in a consist that clearing the consist didn't fix. However, in DecoderPro I could reset the consist CVs and it worked fine.
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Post by canrailfan on Aug 20, 2020 7:54:02 GMT -8
As Ed said, the short would not draw excess power through the decoder. However the derailment and short could have generated a voltage spike that could have caused damage.
I'm not familiar with the SD70ACE internal set-up but assume you are plugging the 8-pin decoder into the Athearn motherboard. There is a possibility that something has been blown on the motherboard and that your decoders are okay.
Have you tested the decoders with a decoder tester or in a different locomotive? That would be my next step.
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Post by brammy on Aug 20, 2020 8:15:39 GMT -8
Have you tested the decoders with a decoder tester or in a different locomotive? That would be my next step. Yeah, my feeling is the Athearn board is toast. I do have a spare loco I can test the decoder in. I think it is unlikely both decoders are shot. That said, at some point I wanted to drop a Loksound in there. On the good side, if there was a loco to go out of commission, this is the one for me. |
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Post by edwardsutorik on Aug 20, 2020 12:13:40 GMT -8
brammy,
It looks like you're doing a fine job of figuring this out.
This seems to be an example of "black box" repair: You change things, and see if the problems stays or migrates. For example, you tried running other locos, and they run fine. Thus probably not your cab. With "black box", you may never know what really failed. You just know which "black box" failed, and you replace it.
Ed
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jimbo
New Member
Posts: 5
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Post by jimbo on Aug 21, 2020 6:24:10 GMT -8
Likely the Athearn board is the problem, I have had a number of them go bad, I always remove them now and start fresh with better results.
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Post by brammy on Sept 11, 2020 18:28:02 GMT -8
So, as they say in the thriller movies, "The short was coming from inside the locomotive, man."
I took it apart tonight and hit everything with the meters. It all looked ok. Heck it even ran when it was apart.
As near as I can tell, Athearn instead of running a single wire from the back headlights (well, two for each lead), spliced one. That one had gotten unspliced. I am not good at soldering that thin a connection so I taped off the two ends. Something was still a little off electrically so I used a liberal amount of insulating tape on the top and bottom of the board. The back headlight doesn't work, but oh well.
At some point I am going to have someone drop a loksound in there which will clean up the wiring mess.
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